Optical fluid-level switch and controls for bilge pump apparatus

Abstract

An optical bilge pump apparatus has two optical fibers with gaps cut therein and associated light transmitters-receivers. The apparatus is responsive to high and low liquid levels in the pump such that the pump is turned on when both gaps in the optical fibers are submersed in liquid, and the pump is turned off when both gaps in the optical fibers are not submersed in liquid.

What is claimed is: 
     
       1. Apparatus comprising: a pump housing;   a motor and impeller mounted within said housing;   an optical switch assembly mounted within said housing to detect liquid levels within said housing;   said assembly including a pair of fiber optic conductors, each conductor having a gap therein; and   said assembly having control means optically coupled to said fiber optic conductors for turning said motor on and off depending the liquid level being above or below each said gap.   
     
     
       2. The apparatus of claim 1, wherein said fiber optic conductors being mounted in parallel and each gap being formed with a bias cut; and   said gap in each of said conductors are displaced one above the other, whereby said control means turns on said motor when said gap in each said conductor is immersed in liquid, and turns off said motor when each said gap is not immersed in liquid.   
     
     
       3. The apparatus of claim 2 including a light emitting diode coupled to each said conductor to transmit light into one end thereof, and a photo transistor coupled to each said conductor to receive light at the other end thereof; and   the transmitted light being coupled and detected when said gap of each conductor is immersed in the liquid, and the transmitted light being refracted and not detected when said gap of each conductor is not immersed in liquid.   
     
     
       4. The apparatus of claim 3 wherein said light emitting diode is an infra-red light emitting diode.   
     
     
       5. The apparatus of claim 4 wherein said control means includes logic circuit means to turn on said motor when said gap in each of said conductor is immersed in liquid, and to turn off said motor when said gap in each of said conductor is not immersed in liquid.   
     
     
       6. The apparatus of claim 5, wherein said logic circuit means includes filter circuit means having a time constant to prevent false start of said motor due to a short duration turbulence in the liquid.   
     
     
       7. In combination: a submersible pump mounted within a pump housing;   relay means coupled to said pump for turning said pump on and off;   optical control means contained within said housing and coupled to operate said relay means;   said optical control means including two optical fibers, each fiber coupled to an associated light transmitter and receiver, and each fiber having a gap, one gap in one fiber at a high liquid level point, and another gap in another fiber at a low liquid level point; and   switch means for energizing said optical control means.   
     
     
       8. The combination of claim 7 wherein said pump is turned on when said one and other gap are both immersed in liquid, and said pump is turned off when said one and other gap are both not immersed in liquid, whereby the light from each said associated light transmitter is refracted at the one and other gap. 
     
     
       9. The combination of claim 8 wherein said associated light transmitter is an infra-red light emitting diode. 
     
     
       10. Optical bilge pump apparatus comprising: a bilge pump;   optical fiber means having gaps therein and being located to detect liquid levels within the bilge pump;   control means to turn the bilge pump on and off depending on changes in light transmission across said gaps due to the presence or absence of liquid; and   said control means including infra-red light emitting and receiving means, and means for converting infra-red light generated electrical signals into switching functions for controlling said bilge pump.   
     
     
       11. Pumping apparatus comprising: a pump housing having an outer wall and an interior wall mounting section;   a motor and impeller mounted to said interior section;   an optical switch assembly mounted to said interior section and within said outer wall to detect liquid levels between said outer wall and said interior section;   said optical switch assembly including an optical fiber body assembly having a pair of fiber optic conductors having gaps therein, said body assembly being located between said outer wall and said interior section; and   said assembly having control means optically coupled to said fiber optic conductors for turning said motor on and off depending the liquid level being above or below said gaps.   
     
     
       12. Pumping apparatus of claim 11, wherein said body assembly retains said fiber optic conductors in a U-shaped parallel configuration, and each said conductor is formed with a bias cut gap therein; and   said gap in each of said conductors are displaced one above the other, whereby said control means turns on said motor when said gap in each said conductor is immersed in liquid, and turns off said motor when each said gap is not immersed in liquid.   
     
     
       13. Pumping apparatus of claim 12 wherein said optical switch assembly includes a light emitting diode coupled to each said conductor to transmit light into one end thereof, and a photo transistor coupled to each said conductor to receive light at the other end thereof; and   said photo transistor detecting the transmitted light when said gap in each said conductor is immersed in the liquid, and the transmitted light being refracted and not detected by said photo-transistor when said gap in each said conductor is not immersed in liquid.   
     
     
       14. Pumping apparatus of claim 13 wherein said light emitting diode is an infra-red light emitting diode.   
     
     
       15. Pump apparatus of claim 14 wherein said control means includes logic circuit means to turn on said motor when said gap in each of said conductor is immersed in liquid, and to turn off said motor when said gap in each of said conductor is not immersed in liquid.   
     
     
       16. Pump apparatus of claim 15, wherein said logic circuit includes filter circuit means having a time constant to prevent false start of said motor due to a short duration turbulence in the liquid.   
     
     
       17. Pump apparatus of claim 16 including: relay means coupled to said pump for turning said pump on and off.   
     
     
       18. Pump apparatus of claim 17 including switch means for energizing said optical control means, and said switch means having an automatic and manual mode for effection on and off control of said motor. 
     
     
       19. Pump apparatus of claim 18 wherein said housing and impeller are formed of a moldable plastic. 
     
     
       20. Pump apparatus of claim 19 wherein said optical fiber conductors are retained in a rigid manner in said body assembly by an epoxy filler. 
     
     
       21. Apparatus for controlling a drive means comprising in combination: a housing having a channel for containing a liquid therein;   optical control means contained within said channel and coupled to operate said drive means;   said optical control means including two optical fibers, each fiber coupled to an associated light transmitter and receiver, and each fiber having a gap, one gap in one fiber at a high liquid level point in said channel, and another gap in another fiber at a low liquid level point in said channel; and   switch means for energizing said optical control means.   
     
     
       22. The combination of claim 21 wherein said drive means is turned on when said one and other gap are both immersed in said liquid, and said drive means is turned off when said one and other gap are both not immersed in said liquid, whereby the light from each said associated light transmitter is refracted at the one and other gap. 
     
     
       23. The combination of claim 22 wherein said associated light transmitter is an infra-red light emitting diode.